Power management integrated circuits manage power requirements for larger systems, such as cell phones, tablets, and other devices. Power management integrated circuits perform various functions related to the power requirements. Some common functions include DC to DC conversion, battery charging, power source selection, voltage scaling, frequency scaling, and power sequencing.
Power management integrated circuits include converters for voltage step-up/step down and for power factor correction. A parallel chopper or “boost” converter, converts DC-to-DC power with an output voltage greater than its input voltage. Boost converters contain at least two semiconductor switches (a diode and a transistor) and at least one energy storage element, a capacitor, inductor, or the two in combination. A series chopper or “buck” converter is a step-down DC to DC converter that reduces an input voltage from a power supply to a lower output voltage for use by a load. Its design is similar to the step-up boost converter, and like the boost converter, it is a switched-mode power supply that uses two switches (a transistor and a diode), an inductor and a capacitor.
Switching converters are indispensable components in battery-powered portable devices for their high efficiency. With more and more complicated and highly-integrated system-on-chip (SoC) designs, fast transient responses are crucial for switching converters to fit the demands of SoC. Hysteretic control provides fast response; however, complicated delay compensation scheme is required in order to fix the switching frequency to achieve a predictable noise spectrum.
On the other hand, pulse-width-modulation control has been attractive for its well predictable and manageable noise spectrum due to the fixed switching frequency. However, pulse-width-modulation control has limited loop bandwidth and low slew-rate of the inductor current and hence the transient response is very slow. The hybrid supply module, which consists of a parallel operation of switching converter and linear regulator, has the potential to be a successful combination of good power efficiency and high loop bandwidth. However, the existing hybrid control schemes either have poor efficiency, cannot be directly applied in a DC-DC converter, or do not target at fast transient response, or need a third party to inform the happening of load transients and hence have limited applicability.
The above-described background is merely intended to provide an overview of contextual information regarding power management integrated circuit devices, and is not intended to be exhaustive. Additional context may become apparent upon review of one or more of the various non-limiting embodiments of the following detailed description.